Adjust Brightness Settings
Most laptops have brightness controls on the keyboard, and it’s possible that bumping one of these keys has dimmed the screen. Look on your keyboard for a sun icon; if the icon is in blue or gray, you need to use the “Function” key to access it. Tap the key to adjust the brightness. If the screen dims further, tap the key beside it to raise the brightness.
Power Saving Mode
Your laptop has different power profiles to prolong battery life once you disconnect the computer from AC power. A basic power-saving plan will, by default, immediately dim the laptop’s screen in order to save power when your computer is running on battery. Your screen going dim could be as simple as that — the power cord connecting the laptop to the wall isn’t connected properly, and the computer is running on battery. Sometimes, a computer can get stuck in its power-saving mode, which would mean that your screen would remain dim after you wake the computer up; reboot your computer to reset power saving mode.
Go into “Control Panel” and then “Power Options”.
2. Click the “Change plan settings” link next to which ever plan you are currently using and then click “Change advance power settings”.
3. In this new window click “Display” to open up the listings under it.
4. Now locate and click each of the following…”Display brightness”, “Dimmed display brightness” and “Enable adaptive brightness”.
5. Change each of these to the settings you wish, then click the “Apply” button and finally the “OK” button.